Spark-plug for explosion-engines.



F. C. WALSH.

SPARK PLUG FOR EXPLOSION ENGINES.

APPLICATION FILED 001'. 2a, 1911.

Patented 0011.. 21, 1913.

FRANK C. WALSH, 'OF CLEVELAND, OHIO, ASSIGNOR 'romm seamsna-ak rave com- PANY, 0F CLEVELAND, OHIO, A CDRI'ORATITON OF OHIO.

SPARK-PLUG E08 EXPLOSION-ENGINES.

To all whom it may concern:

Be it known that I, FRANK O. VVALs a citizen of the United States, and resident of Cleveland, in the county of Ouyahoga and State of Ohio, have invented certain new and useful Improvements in Spark-Plugs for- Explosion-Engines, of which I hereby declare the following to be a full, clear, and exact description, such as will enable others skilled in the art to which it appertains to make and use the same.

The objects of the invention are to provide the insulation of a spark plug with expansion joints, so arranged and constructed that the joints will always be perfectly gas tight and yet .sufiicient pressure will not be exerted upon the porcelain insulation to crack it when the joints contract afterthey have been exposed to a high degree of temperature.- The sparking extremity of the plug is also constructed and arranged to givea large annular opening about the sparking tips so that all carbon will be cleared ofl from the metal parts by the action of the vacuum created by the exhaust and therefore cannot accumulate thereon or upon the porcelain sufliciently to cause a short circuit.

The invention further comprises the combination and arrangement of parts and con struction of details hereinafter described shown in, the accompanying drawings and specifically pointed out in the claims.

In the accompanying drawings Figure 1 is a longitudinal central section of the device; Fig. 2 is an enlarged section of one of the washers forming a tight joint between the insulation and the central conductor at the upper end thereof; Fig. 3 is a similarsectional view of the washer at the lower end thereof and adjacent parts.

In these views 1 is the insulation preferably formed of porcelain.

2 is the outer shell screw threaded at 3 for insertion in the explosion end f the cylinder of an explosion engine.

4 is the clamping sleeve screw threaded at 5 for attachment to the screw threaded upper end of the shell 2. The lower portion of the shell is cylindrical and open as shown at 6. The porcelain is formed with an annular enlargement 7 intermediate its ends and is provided with a central opening 8. The lower extremity 9 is preferably tapered and the upper portion 10 is cylindrical.

The electrode 11 passes centrally through Specification of Letters Patent.

Application filed October 28, 1911.

Patented Oct. 21, 1913. Serial No. 657,268.

the opening 8 in the porcelain and is screw threaded at its upper extremity at 12, for the attachment of the clam ing nuts 13 and 14 between which the con uctor wire 15 is secured. a

16 is an intermediate washer or expanded base of the nut, and 17 is an expanding washer intermediate the part 16 and the top of the porcelain.

The lower end 'of the electrode 11 is enlarged in the shape of a downwardly extending cone 18 having a fiat shoulder 19 and terminates in a short straight portion 20 in which a short firing wire 21 is inserted. The other terminal 22 is inserted in the lower end of the shell and is bent at an angle to overlap the terminal 21 leaving-a space between them for the production of the arc.

The opening 6 is cylindrical and gives free action to the effect of the exhaust so that the conical extremity 18 of the electrode 11 will always free itself from carbon deposit and contact between the outer shell and the conical terminal can never be completed or maintained if it accidentally occurs, for the reason that the vacuum created by the exhaust will draw 011' the carbon dried by the heat of the explosion.

fBetween the shoulder 19 and the lower end 0 washer 24. The porcelain is secured rigidly in place by tightening the clamping nuts 13 and 14. The electrode 11 is purposely formed of low grade carbon steel so that it will heat readily at the time of the explosion and thoroughly dry the oilwhiclr. may collect upon it from the cylinder, so that the carbon formed will be in the nature of a dry powder and the force of the exhaust will carry ofi the deposit. The conical extremity will become sufliciently heated to immediately dry up any. deposit of oil or carbonaceous matter of any kind.

The expansion washers are formed of annealed sheet copper with the edges crimped over inclosing fiat asbestos rings R. The extremities of the porcelain engage and press against the asbestos rings and the turned over edges of the copper washers engage the sides of the porcelain.

To insure a tight joint against loss of compression gases the margin of the porcelain is beveled at B and engages the crimped over margin of the copper washer, while the body portion of the ends of the the porcelain is inserted the expansion porcelain engage the flat asbestos rings which receive the greater part of the strain upon the porcelain. The crimped edges are resilient and the asbestos is compressible thus providing gas tight joints at both ends of the porcelain. The washers cover the extremities of the porcelain so that the strain is distributed over the entire faces of the ends thereof. The beveled edges of the porcelain are forced int-o the crimped edges of the copper portions of the washers, and the faces F, F engage the flat sides of the asbestos rings. The copper portions'of the washers are made of soft annealed copper and this fact with the bent over edges give resiliency at all times so that the porcelain is clamped with resilient pressure at both ends. The annealed copper will contract after heating to the same position as it assumed when first put in its place, so that there, will be no danger of the porcelain becoming cracked from any increase of pressure, due to subsequent contractions.

To insure a uniform action of washer and electrode in contracting and expanding, the electrode is formed of low grade carbon steel, and the copper in the washer is annealed so that these parts will expand and contract in unison, whereas if the copper in the washers were formed of unannealed material the contraction after they were ex posed to an annealing heat would be much greater than in the unannealed state and hence would be suflicient to crack the percelain. The low grade of carbon steel of which the electrode is composed is also quickly absorbent of heat and the conical extremity will therefore heat readily. The short cylindrical extension of the electrode is employed to assist in collecting the heat required to dry the oil which may be deposited upon the lower end of the electrode and forms a base in which a short section of meteor wire is inserted for the firing wire and provides a rigid support for the firing Wire so as to maintain a spark gap which will not vary in width, since the wire is short and will not have a tendency to warp under extreme heat. It is well known that meteorwire is not afiected to fusion by the extreme heat of the spark, and of the explosion. The clamping sleeve or gland nut 4 described is beveled at its inner end at X and engages a copper asbestos washer W resting on a square shoulder S on the porcelain. This construction afiords ameans for centering the porcelain accurately and provides a gas tight joint in connection with a second copper and asbestos gasket W restin on a shoulder S on the shell, and engaglng a shoulder S on the porcelain.

Having described the invention what I claim as new and desire to secure by Letters Patent is:

1. In a spark plug, the combination with a porcelain insulation having flat extremities and beveled edges, and an electrode passing through said insulation, of clamping means for the porcelain, said clamping means secured on said electrode, and washers introduced between said clamping means, and said insulation, said washers composed in part of annealed copper having inwardly crimped edges, and part of as bestos, the flat extremities of said insulation engaging said asbestos portion, and the beveled edges engaging the said crimped edges of the copper.

2. In a spark plug, in combination, a porcelain insulation, and an expansible electrode passing therethrough, a clamping means therefor, said insulation provided with flat extremities having beveled edges, clamping means for said electrode, and annealed expansible washers interposed be tween said porcelain and said clamping means, said washers provided with inwardly crimped edges engaging said beveled edges of said insulation, and asbestos rings in said copper washers engaging the flat extremities of said porcelain.

In testimony whereof, I hereunto set my hand this 23 day of October 1911.

FRANK G. WVALSH.

Witnesses:

WM.- M. Mormon, MAX I. GOODMAN. 

